@article{ref1,
title="Studying categorical data over time",
journal="Social science research",
year="1978",
author="Davis, James A.",
volume="7",
number="2",
pages="151-179",
abstract="A review of recently developed simple techniques for analyzing data in the form of proportions from replicated, cross-sectional, sample surveys. (A) One variable over time--tests for homogeneity, pooling homogeneous proportions, tests for linear trends with as few as three time points, tests for departures from linearity; (B) Two variables with a constant percentage difference--four fold tables as rudimentary causal models, decomposing change with linear flow graphs; (C) Extension of the flow graph techniques to--three or more variables and changing coefficients; (D) Comments implying panel designs are somewhat over-rated and successive cross-sections somewhat under-rated.<p />",
language="en",
issn="0049-089X",
doi="10.1016/0049-089X(78)90009-1",
url="http://dx.doi.org/10.1016/0049-089X(78)90009-1"
}